rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=d574/1/0x4000000000000000 softirq=43731/43732 fqs=2 rcu: (detected by 1, t=10502 jiffies, g=27737, q=2186 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5196 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:100 [inline] RIP: 0010:memory_is_nonzero mm/kasan/generic.c:115 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:140 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline] RIP: 0010:kasan_check_range+0x150/0x1b0 mm/kasan/generic.c:200 Code: 11 80 38 00 74 ef 4d 8d 1c 2c 48 89 c2 48 85 c0 75 ad 48 89 da 4c 89 d8 4c 29 da e9 46 ff ff ff 48 85 d2 74 18 48 01 ea eb 09 <48> 83 c0 01 48 39 d0 74 0a 80 38 00 74 f2 e9 75 ff ff ff 5b b8 01 RSP: 0018:ffffc90000007d00 EFLAGS: 00000046 RAX: ffffed100f05f890 RBX: ffffed100f05f891 RCX: ffffffff8967f5f0 RDX: ffffed100f05f891 RSI: 0000000000000004 RDI: ffff8880782fc480 RBP: ffffed100f05f890 R08: 0000000000000001 R09: ffffed100f05f890 R10: ffff8880782fc483 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880782fc400 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007fa0483a2880(0000) GS:ffff888124e77000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0a44ebff98 CR3: 0000000022a99000 CR4: 00000000003526f0 Call Trace: instrument_atomic_write include/linux/instrumented.h:82 [inline] atomic_set include/linux/atomic/atomic-instrumented.h:67 [inline] taprio_set_budgets+0x1a0/0x310 net/sched/sch_taprio.c:677 advance_sched+0x5f6/0xc80 net/sched/sch_taprio.c:982 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_const_cmp2+0x8/0x20 kernel/kcov.c:307 Code: b6 f7 bf 01 00 00 00 e9 86 fe ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 0c 24 <0f> b7 d6 0f b7 f7 bf 03 00 00 00 e9 58 fe ff ff 0f 1f 84 00 00 00 RSP: 0018:ffffc90003e9f9f8 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffff88807ddbacb8 RCX: ffffffff8238f825 RDX: 1ffff1100fbb7597 RSI: 0000000000004000 RDI: 0000000000006000 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000004000 R13: 0000000000000000 R14: ffffffff8262de60 R15: ffff88807ddbacba devcgroup_inode_permission include/linux/device_cgroup.h:21 [inline] inode_permission+0x115/0x630 fs/namei.c:597 may_lookup fs/namei.c:1858 [inline] link_path_walk+0x197/0xe20 fs/namei.c:2467 path_openat+0x1b0/0x2cb0 fs/namei.c:4130 do_filp_open+0x20b/0x470 fs/namei.c:4161 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa047ca7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffd82b291f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fa0483a2880 RCX: 00007fa047ca7407 RDX: 0000000000080000 RSI: 00007ffd82b29370 RDI: ffffffffffffff9c RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000564837dd67f5 R13: 0000564837dd67f5 R14: 0000000000000001 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10498 jiffies! g27737 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:28144 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x56d/0x730 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 9017 Comm: syz.4.843 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x10/0x70 kernel/kcov.c:217 Code: 00 00 5b e9 72 ba e6 02 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 34 24 65 48 8b 15 d8 7c bf 11 <65> 8b 05 e9 7c bf 11 a9 00 01 ff 00 74 1d f6 c4 01 74 43 a9 00 00 RSP: 0018:ffffc9000585f928 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff8880b8642800 RCX: ffffffff81af06a1 RDX: ffff88802a960000 RSI: ffffffff81af067b RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffed10170c8501 R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124f77000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30723ffc CR3: 000000005d14a000 CR4: 00000000003526f0 Call Trace: native_pause arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xdfb/0x1600 kernel/smp.c:877 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x4a0/0x17a0 arch/x86/mm/tlb.c:1451 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline] tlb_flush_mmu mm/mmu_gather.c:403 [inline] tlb_finish_mmu+0x3c9/0x7c0 mm/mmu_gather.c:497 exit_mmap+0x3fc/0xb90 mm/mmap.c:1293 __mmput+0x12a/0x410 kernel/fork.c:1133 mmput+0x62/0x70 kernel/fork.c:1156 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:954 do_group_exit+0xd3/0x2a0 kernel/exit.c:1107 __do_sys_exit_group kernel/exit.c:1118 [inline] __se_sys_exit_group kernel/exit.c:1116 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1116 x64_sys_call+0x150b/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f03e5f8eec9 Code: Unable to access opcode bytes at 0x7f03e5f8ee9f. RSP: 002b:00007ffe69d39c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f03e5f8eec9 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffe69d39ccc R08: 0000000869d39d5f R09: 00000000000927c0 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000000c3 R13: 00000000000927c0 R14: 0000000000052b00 R15: 00007ffe69d39d20 sched: DL replenish lagged too much